Question

The standard electrode potentials of three metals A, B and C are, respectively, + 0.34 V, - 1.18 V and - 0.25 V. The correct order of reducing power of these metals is :

• A. B $\gt $ C $\gt $ A
• B. A $\gt $ B $\gt $ C
• C. C $\gt $ B $\gt $ A
• D. A $\gt $ C $\gt $ B

Hint:

Lower (more negative) Reduction Potential = Higher Reducing Power.

Answer 1

The Correct Option is A

Step 1: Connect standard electrode potential to reducing power.
Standard reduction potential ($E^\circ$) measures the tendency of a species to gain electrons (be reduced). Reducing power is the opposite: the tendency to lose electrons (be oxidised). The more negative $E^\circ$, the stronger the reducing agent.
Step 2: List the given values.
Metal A: $E^\circ = +0.34$ V; Metal B: $E^\circ = -1.18$ V; Metal C: $E^\circ = -0.25$ V.
Step 3: Rank from most negative to least negative.
Ascending $E^\circ$ order: B ($-1.18$ V) $\lt$ C ($-0.25$ V) $\lt$ A ($+0.34$ V). The more negative the $E^\circ$, the greater the tendency to be oxidised.
Step 4: State the reducing power order.
Metal B is the strongest reducing agent, followed by C, then A.
\[ \boxed{B \gt C \gt A} \]